Preceden supports a handful of keyboard shortcuts:
Add an event
Ctrl/Cmd + A
Esc (when viewing a timeline)
Close a dialog (without saving any changes)
Drag an event left and right
Hold shift then click and hold down on an event to drag it left and right if the event supports it.
Scroll horizontally while zoomed in
Use the left and right arrow keys
Submit a form from the notes area
If you're editing event/layer/timeline notes and want to submit the changes you've made, you can press Ctrl/Cmd + Enter.
This is necessary because notes let you press enter to create multiple paragraphs, so by holding Ctrl/Cmd with it you're telling Preceden you want to submit the form and not create a new paragraph.